Container thermoforming installations equipped with decorated or undecorated banderole preforming and transfer means are generally known from German Utility Model No. 1 969 306, and from French Pat. Nos. 2 034 915 and 2 256 013. In the case of the German Utility Model and of French Pat. No. 2 034 915, the banderole is introduced into the forming chamber through the front opening thereof, so that the forming chambers should be moved sideways or be tilted about a horizontal axis in order to become accessible to the corresponding banderoles prepared in a pre-forming and transfer device.
In the case of French Pat. No. 2 256 013, the banderoles are introduced through the open base of the forming chambers beneath which is placed the banderoles pre-winding and transfer unit which has no shaping member.
Banderoles preforming and transfer devices equipped with one shaping member for every forming chamber in the molding unit superposed to the banderoles pre-winding unit are known for example from French Pat. Nos. 2 339 474, 2 340 185, 2 342 145, 2 528 349 and 2 528 355. One of the disadvantages found with these known pre-forming devices is that the upstream end of the individual band from which the banderole is cut is at a certain distance from the pre-winding chamber and has to be introduced therein (French Pat. Nos. 2 340 185, 2 528 349 and 2 528 355) or that the end of the individual band must be withdrawn from the access slot into the pre-winding chamber after the cutting of a banderole (French Pat. Nos. 2 339 474, 2 342 145 and 2 528 355), this screating a non-productive time and entailing risks of the banderole or of the free end of the individual band being jammed during the pre-winding cycle of the next banderole.
Shaping members adapted to penetrate into the forming chamber through the base thereof and which are operationally coupled to a transfer member provided in the pre-winding chamber have already been proposed for example in French Pat. Nos. 2 350 190, 2 528 349 and 2 528 355.
In the case of Pat No. 2 350 190, the time available for winding the banderole and cutting it in the pre-winding chamber is maximum compared with the time allowed between two successive banderole transfer runs from the pre-winding chamber to the shaping chamber, but this embodiment requires a complicated mechanical structure which is relatively delicate and as such does not permit high moving speeds of the molding unit between its forming position and its transfer position. Similar problems occur in the case of Pat. Nos. 2 528 349 and 2 528 355.
It is found that in the known devices, and because of the relative positions between the forming chamber, the banderole introduction and cutting unit and the transfer member, the time allocated for the preparation of a wound banderole is insufficient. This shortage of time is even more of a problem in the case of the preparation of very long banderoles which, in the pre-winding chamber, should already have a shape very similar to that of the forming chamber.